Regular Article

Sorption of natural gas in cement hydrate by Monte Carlo simulation

Department of Chemical Engineering, Mangosuthu University of Technology, 511 Griffiths Mxenge Highway, Durban 4031, South Africa

^a e-mail: lasich.matthew@mut.ac.za

Received: 25 May 2018
Received in final form: 21 August 2018
Published online: 3 December 2018

Abstract

Concrete, a combination of cement, water, sand, and aggregates, is a ubiquitous engineering and construction material. This composite material is exposed to a wide variety of environmental conditions that can cause degradation, such as extremes of temperature, and exposure to corrosive substances. This study is concerned with the sorption of natural gas constituents and their mixtures in cement hydrate using atomistic Monte Carlo simulation in the grand canonical ensemble. Pure species sorption isotherms were generated at 273, 298, and 323 K for gas fugacities up to 10³ kPa. Comparison of gas uptake and the isosteric heat of adsorption in cement was undertaken for all of the species in the study, and the influences of both temperature and gas fugacity on sorption characteristics were considered. The selectivity of adsorption of hydrogen sulphide in a natural gas blend was also considered, as it is typically responsible for the degradation of concrete infrastructure.